You might need to be more specific about what light you're seeing. If it is a light in the shape of a battery on your dash then this a problem with your charging system. Your alternator might be bad or there may be some other electrical issue.

If the light is the check engine light then do this:

1) Turn off your car and open the door after removing your key to make sure all power is off
2) Without actually turning the engine on do this sequence fast: On-Off-On-Off-On
3) The information display will read your car for a code and then display the code, or series of codes, to identify the problem

If this is the case come back here and let me know what the code is and I'll try to help.

Im getting a Service Tire Press. Monitoring System alert on my dash every 5 minutes or so, just btw I recently had 4 new tires put on and they had to replace one of the tire sensors but all the sensors are working correctly now, so do i really need to service the tire pressure monitoring system or just ignore it?